Does green tea help with mood swings during perimenopause?

Green tea may offer meaningful support for mood swings during perimenopause, and this is one of the more evidence-supported applications of its active compounds. The L-theanine and caffeine combination found in brewed green tea is well-studied for its effects on mood and mental steadiness, and the anti-inflammatory properties of EGCG add a second mechanism that is particularly relevant during perimenopause.

Mood swings in perimenopause are not simply psychological. Estrogen directly modulates serotonin, dopamine, and GABA neurotransmitter systems in the brain. As estrogen fluctuates erratically, serotonin reuptake rates shift, dopamine receptor sensitivity changes, and the calming influence of GABA decreases. This produces genuine neurochemical instability that can manifest as irritability, low mood, anxiety bursts, and emotional reactivity that feels out of proportion to circumstances. The challenge is real, and it has a physiological basis.

L-theanine is the most directly relevant compound in green tea for mood. It promotes alpha brain wave activity, the mental state associated with calm alertness, and modulates glutamate at NMDA receptors while increasing GABA activity. Several small randomized trials in humans have shown L-theanine reduces subjective anxiety, lowers stress biomarkers, and improves mood under stress conditions. A 2008 RCT by Owen and colleagues showed that L-theanine and caffeine together improved alertness and attention while reducing the jitteriness caffeine alone can produce. The caffeine-L-theanine synergy in green tea means you get a more stable, even mood lift than coffee provides.

EGCG contributes through anti-inflammatory mechanisms. During perimenopause, systemic inflammation rises as estrogen's anti-inflammatory protection decreases. Inflammatory cytokines, including IL-6 and TNF-alpha, can cross the blood-brain barrier and directly impair serotonin production and availability, contributing to low mood and irritability. EGCG inhibits NF-kB, reducing this inflammatory load at the cellular level. Green tea polyphenols also act as prebiotics, supporting gut microbiome diversity. The gut-brain axis connection means that a healthier microbiome may support more stable serotonin production, since a significant proportion of the body's serotonin is produced in the gut.

For practical intake, studies examining L-theanine's mood effects have typically used 100 to 200 mg per serving. A cup of brewed green tea provides roughly 20 to 50 mg L-theanine and 20 to 50 mg caffeine, so the combination effect builds across 2 to 3 cups during the day. Drinking green tea in the morning and around midday, rather than in the afternoon or evening, keeps the caffeine from interfering with sleep, which is itself a major driver of mood instability in perimenopause. If you are caffeine-sensitive, decaffeinated green tea still delivers L-theanine and EGCG, preserving the calming and anti-inflammatory benefits.

Four safety points apply across all green tea use. High-dose green tea supplements (EGCG extracts) have been associated with rare cases of liver toxicity. Choose brewed green tea over high-dose supplements where possible. Caffeine in green tea may worsen anxiety, palpitations, or sleep issues if you are sensitive to stimulants. Consider decaffeinated green tea if this applies. EGCG can reduce iron absorption, so drink green tea between meals rather than with iron-rich foods or iron supplements. If you take warfarin, blood thinners, or certain medications, check with your provider, as green tea contains vitamin K and EGCG affects drug metabolism.

Expect a gradual rather than sudden improvement. Consistent daily intake over four to eight weeks, combined with other stabilizing habits like regular sleep, regular meals to prevent blood sugar swings, and adequate omega-3 intake, is more likely to produce a noticeable shift than green tea alone. Blood sugar stability deserves particular mention alongside mood. Erratic glucose levels, which become more common during perimenopause as insulin sensitivity shifts, produce their own emotional volatility, including irritability, anxiety, and tearfulness. Green tea catechins, particularly EGCG, have been shown in multiple studies to reduce post-meal glucose spikes and improve insulin sensitivity. Stabilizing blood sugar is one of the more underappreciated strategies for steadier mood during this life stage.

See a doctor if mood swings include persistent low mood lasting more than two weeks, significant anxiety that interferes with daily life, suicidal thoughts, or severe irritability and rage that is damaging your relationships. Perimenopause mood changes can be clinically significant and may respond well to targeted treatment. Green tea is a supportive measure, not a substitute for professional care.

The PeriPlan app (https://apps.apple.com/app/periplan/id6740066498) lets you log mood daily so you can spot whether patterns shift over time as you adjust your habits.

This content is for informational purposes only and does not replace medical advice. Always consult your healthcare provider about your specific situation.